A radiofrequency transseptal needle: initial animal studies.

OBJECTIVES: The objective of this study was to demonstrate the safety and efficacy of a new transseptal needle design with a radiofrequency (RF) tip combined with the ease of use of the needle configuration.

BACKGROUND: RF transseptal puncture to enter the left heart, with a RF wire-catheter system is a successful technique in patients with complex access using a standard transseptal needle.

METHODS: The RF transseptal needle (NRG™ Transseptal Needle; Baylis Medical, Montreal, Canada) was designed for RF percutaneous transseptal access to the left heart. Eight pigs underwent transvenous cardiac catheterization with baseline intracardiac electrograms and right atrial pressure waveforms. Transseptal RF puncture was performed followed by left atrial pressure waveform monitoring.

RESULTS: An intracardiac electrogram was recorded in each animal while dragging the needle tip from the superior caval vein across the atrial septum and into the inferior caval vein. Contrast staining of the atrial septum was accomplished in all animals, with subsequent RF septal puncture. After 0.1 sec, impedance increased from 300 to 1,200 Ohms with the creation of a vapor layer, and voltage increased steadily to a threshold of 230 volts over the first 0.4 sec. This dielectric breakdown results in tissue vaporization and tissue perforation. The needle's location within the left atrium was confirmed by the pressure waveform and contrast injection. Repeated RF punctures with the NRG™ was compatible with various manufactures transseptal sheaths.

CONCLUSION: RF puncture of the interatrial septum using the NRG™ Transseptal Needle facilitates an alternative effective technique to enter the left atrium. © 2010 Wiley-Liss, Inc.